From: Borislav Petkov <bp@alien8.de>
To: Jarkko Sakkinen <jarkko@kernel.org>
Cc: linux-sgx@vger.kernel.org,
Dave Hansen <dave.hansen@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/2] x86/sgx: Do not update sgx_nr_free_pages in sgx_setup_epc_section()
Date: Wed, 7 Apr 2021 18:18:11 +0200 [thread overview]
Message-ID: <20210407161811.GK25319@zn.tnic> (raw)
In-Reply-To: <YG3X454GI4U2BZVU@kernel.org>
On Wed, Apr 07, 2021 at 07:03:47PM +0300, Jarkko Sakkinen wrote:
> > Which leads to my question: what is sgx_nr_free_pages supposed to denote?
> >
> > Because I understand the callpath
> >
> > sgx_page_cache_init
> > ...
> > for (i = 0; i < ARRAY_SIZE(sgx_epc_sections); i++) {
> > ...
> > sgx_setup_epc_section
> > ...
> > sgx_nr_free_pages += nr_pages;
> >
> > as adding the number of pages of each new EPC section to the total
> > number of the free pages. Unless that variable accounts something else.
> >
> > So what does this variable actually mean?
>
> It's used for only to trigger watermark for reclaiming. I.e. causes
> ksgxd to trigger. And it gives the number of total free EPC pages in
> all NUMA nodes.
So the callpath I laid out above is adding the number of pages of each
section to the total free EPC pages number.
Why is that wrong and why is your patch needed?
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2021-04-07 16:18 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-05 23:26 Jarkko Sakkinen
2021-04-05 23:26 ` [PATCH v2 2/2] x86/sgx: Add sgx_nr_{all, free}_pages to the debugfs Jarkko Sakkinen
2021-04-07 15:56 ` Borislav Petkov
2021-04-07 16:09 ` Jarkko Sakkinen
2021-04-07 16:15 ` Borislav Petkov
2021-04-08 8:52 ` Jarkko Sakkinen
2021-04-08 9:01 ` Borislav Petkov
2021-04-08 9:13 ` Jarkko Sakkinen
2021-04-08 9:32 ` Borislav Petkov
2021-04-08 16:27 ` Jarkko Sakkinen
2021-04-07 15:49 ` [PATCH v2 1/2] x86/sgx: Do not update sgx_nr_free_pages in sgx_setup_epc_section() Borislav Petkov
2021-04-07 16:03 ` Jarkko Sakkinen
2021-04-07 16:18 ` Borislav Petkov [this message]
2021-04-08 8:48 ` Jarkko Sakkinen
2021-04-08 8:56 ` Borislav Petkov
2021-04-08 9:22 ` Jarkko Sakkinen
2021-04-08 9:29 ` Borislav Petkov
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